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bus: mhi: core: Add support for forced PM resume

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For whatever reason, some devices like QCA6390, WCN6855 using ath11k
are not in M3 state during PM resume, but still functional. The
mhi_pm_resume should then not fail in those cases, and let the higher
level device specific stack continue resuming process.

Add an API mhi_pm_resume_force(), to force resuming irrespective of the
current MHI state. This fixes a regression with non functional ath11k WiFi
after suspend/resume cycle on some machines.

Bug report: https://bugzilla.kernel.org/show_bug.cgi?id=214179

Link: https://lore.kernel.org/regressions/871r5p0x2u.fsf@codeaurora.org/
Fixes: 020d3b26c0 ("bus: mhi: Early MHI resume failure in non M3 state")
Cc: stable@vger.kernel.org #5.13
Reported-by: Kalle Valo <kvalo@codeaurora.org>
Reported-by: Pengyu Ma <mapengyu@gmail.com>
Tested-by: Kalle Valo <kvalo@kernel.org>
Acked-by: Kalle Valo <kvalo@kernel.org>
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
[mani: Switched to API, added bug report, reported-by tags and CCed stable]
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20211209131633.4168-1-manivannan.sadhasivam@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Loic Poulain 2021-12-09 18:46:33 +05:30 • committed by Greg Kroah-Hartman
parent 7c602f5d04
commit cab2d3fd68
3 changed files with 36 additions and 4 deletions
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13
include/linux/mhi.h
View file

@ -663,6 +663,19 @@ int mhi_pm_suspend(struct mhi_controller *mhi_cntrl);
*/
int mhi_pm_resume(struct mhi_controller *mhi_cntrl);
/**
* mhi_pm_resume_force - Force resume MHI from suspended state
* @mhi_cntrl: MHI controller
*
* Resume the device irrespective of its MHI state. As per the MHI spec, devices
* has to be in M3 state during resume. But some devices seem to be in a
* different MHI state other than M3 but they continue working fine if allowed.
* This API is intented to be used for such devices.
*
* Return: 0 if the resume succeeds, a negative error code otherwise
*/
int mhi_pm_resume_force(struct mhi_controller *mhi_cntrl);
/**
* mhi_download_rddm_image - Download ramdump image from device for
* debugging purpose.